POS1479 MORTALITY OUTCOMES IN SYSTEMIC LUPUS ERYTHEMATOSUS: A STUDY OF THE BATH LUPUS COHORT
Authors: J. Ellis, E. Korendowych, S. Skeoch
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The Bath CTD cohort study contains a mixed prevalent and inception cohort of 281 SLE patients recruited between 2001 and 2018 from outpatient Rheumatology clinics at the Royal United Hospital for Rheumatic Diseases, Bath,UK. Work from other lupus cohorts in the UK (1) has demonstrated residual poor mortality outcomes for SLE patients. We set out to describe mortality outcomes for our local cohort of SLE patients, with reference to expected trends and autoantibody profiles. <h3>Objectives:</h3> 1) Describe mortality outcomes (proportion of cohort, age of death and cause of death) from a longitudinal cohort of SLE patients. 2) Calculate prematurity of death (years of life lost) for deceased patients with reference to estimated mortality reference figures for the UK population. 3) Compare autoantibody profiles between deceased and non-deceased patients to assess for associations between mortality and patient serology. <h3>Methods</h3> Data was extracted from secure research databases. Copies of death certificates where obtained. Estimated life expectancy (for year of birth and gender) was calculated using Office of National Statistics (ONS) data. Years of life lost (or gained) was calculated. A paired samples t-test was performed to compare the difference between age at death and predicted age at death for the deceased cohort. Autoantibody profiles between deceased and non-deceased patients were compared using Chi squared (Fisher's exact test if n &lt;5) and relative risks, confidence intervals and p values calculated. <h3>Results</h3> The cohort comprised 251 female and 30 male patients. Average age at diagnosis was 37.9 (18 to 62). 97% were ANA positive. 21% (61/281) of the cohort had died. Proportionally more male (13/30) than female (48/251) patients died. Cause of death data was available for 60 patients. The most common causes of death were malignancy (23.3%, 14/60), cardiovascular (21.6%, 13/60) and infection (18.3%,11/60). 8 patients (13.3%) died of SLE. 21 patients died earlier than their predicted life expectancy (-1.5 to – 32.6 years less). Mean of the difference (between actual and predicted life expectancy) for the cohort was + 4.64 (95% CI 0.4281 to 8.854, p value 0.0314). Patients that died early were more likely to die of SLE (20%, 4/20 vs 10%, 4/40), infection (15%,3/20 vs 20%, 8/40) and malignancy (40%,8/20 vs 15%, 6/40) vs than those who died late. Those who died later more likely to die of cardiovascular disease (28%,11/40 vs 10%, 2/20). Numerically those who died early were more likely to be male, older at diagnosis and be dsDNA+ve, but these numbers did not reach statistical significance. No significant differences in autoantibody profiles were detected between deceased and non-deceased patients. <h3>Conclusion</h3> We observed a bimodal distribution of causes of death, with SLE, malignancy and infection more likely to cause early deaths, and cardiovascular disease more likely to cause later deaths. Across the whole cohort, patients lived longer than was expected. However, a third of patients still died early, suggesting future work should focus on addressing these highest risk patients. Across the cohort proportionally more male than female patients died. This may reflect known differences in life expectancy between genders, but highlights male patients as a group with persisting poorer mortality outcomes. No significant differences in autoantibody profiles were observed between patients that died versus those that survived. This may be because the entire cohort is enriched for positive serology, perhaps making it less likely that differences will be identified. <h3>Reference</h3> [1]Segura BT, Bernstein BS, McDonnell T, Wincup C, M Ripoll V, Giles I, Isenberg D, Rahman A. Damage accrual and mortality over long-term follow-up in 300 patients with systemic lupus erythematosus in a multi-ethnic British cohort. Rheumatology (Oxford). 2020 Mar 1;59(3):524-533. doi: 10.1093/rheumatology/kez292. Erratum in: Rheumatology (Oxford). 2020 Mar 1;59(3):698. PMID: 31377781; PMCID: PMC8414923. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.